Many porous substrates, such as wood or concrete, are susceptible to damage from biomatter such as bacteria, fungi such as mold and mildew, and algae. Many protective coatings applied to such substrates may fail mechanically over time. For example, protective coatings may crack from the stress of thermal cycling (e.g., from weather conditions), or they may be damaged by impact or may sustain scratches from use. These damage sites quickly become areas where the underlying substrate is exposed, and biomatter can begin to grow, causing further damage to the protective coating and/or underlying substrate.